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EP-4316648-B1 - ADSORPTION SHEET AND PRODUCTION METHOD THEREFOR

EP4316648B1EP 4316648 B1EP4316648 B1EP 4316648B1EP-4316648-B1

Inventors

  • KITAHARA HIROSHI
  • MURAMATSU DAISUKE
  • MIYAHARA KAORI
  • INOUE TATSUNARI

Dates

Publication Date
20260506
Application Date
20220309

Claims (7)

  1. An adsorption sheet obtained by forming a single layer of an adsorptive composition, the adsorptive composition comprising, out of a total solid content of 100% by mass, 20 to 80% by mass of an adsorbent, 12 to 75% by mass of a melt-resistant fiber with a high beating degree which is composed of a fiber that has a beating degree of 50 to 500 ml CSF and does not melt at a temperature of 150°C, and 2 to 12% by mass of a binder, wherein said adsorptive composition further comprises 2 to 66% by mass of a melt-resistant fiber with a low beating degree which is composed of a fiber that has a beating degree of 550 to 750 ml CSF and does not melt at a temperature of 150°C.
  2. The adsorption sheet according to Claim 1, wherein said melt-resistant fiber with a high beating degree has an average fiber length of 0.5 to 2.5 mm, an average fiber width of 16 to 35 µm, and an aspect ratio of 30 to 80.
  3. The adsorption sheet according to Claim 1, wherein said melt-resistant fiber with a low beating degree has an average fiber length of 2.6 to 10 mm, an average fiber width of 2 to 10 µm, and an aspect ratio of 300 to 1,250.
  4. The adsorption sheet according to Claim 1 or 3, wherein a beating degree of fibers obtained by combining said melt-resistant fiber with a high beating degree and said melt-resistant fiber with a low beating degree is from 50 to 500 ml CSF.
  5. The adsorption sheet according to Claim 1, wherein said adsorptive composition either further contains, at a ratio of 25% by mass or less, a hot melt fiber composed of a fiber that melts at a temperature of 150°C, or does not contain said hot melt fiber.
  6. The adsorption sheet according to any one of Claims 1 to 5, wherein said adsorption sheet has a basis weight of 40 to 150 g/m 2 .
  7. A method for producing the adsorption sheet according to any one of Claims 1 to 6, which is a method for producing an adsorption sheet by subjecting a slurry comprising said adsorptive composition to paper making by a wet papermaking process.

Description

[Technical Field] The present invention relates to an adsorption sheet and a method for producing the same. Priority is claimed on Japanese Patent Application No. 2021-050988, filed March 25, 2021. [Background Art] In order to maintain the freshness of greengrocery such as vegetables and fruits, materials that adsorb ethylene gas are known. For example, Patent Document 1 describes a food packaging sheet in which a fine powder of a soft porous ancient marine humic substance that forms super porous pores having ethylene gas adsorption capacity is uniformly supported on the surface of a sheet-like carrier. Patent Document 2 describes an ethylene adsorption material in the form of a paper sheet or film loaded with adsorbent. [Citation List] [Patent Document] [Patent Document 1] Japanese Examined Patent Application, Second Publication No. Hei 8-25257[Patent Document 2] European Patent Application 1 525 802 A1 [Summary of Invention] [Technical Problem] However, since the conventional ethylene gas adsorption sheet assumes a gas emitted from fruits and vegetables, the amount of gas adsorbed per unit time was small. For this reason, it is not suitable for use in, for example, adsorption of gas that is instantaneously generated in large amounts. In order to increase the amount of gas adsorbed, a method of increasing the amount of adsorbent supported on the sheet is conceivable. However, when the amount of supported adsorbent increases, the adsorbent is not uniformly dispersed on the surface of the sheet, making it difficult to maintain an amount of adsorption corresponding to the amount of supported adsorbent. In order to solve the above-mentioned problems, the present invention provides: an adsorption sheet that can increase the amount of adsorption by uniformly supporting an adsorbent on the sheet even when the amount of supported adsorbent is increased; and a method for producing the same. [Solution to Problem] A first aspect of the present invention is an adsorption sheet obtained by forming a single layer of an adsorptive composition, the adsorptive composition containing, out of a total solid content of 100% by mass, 20 to 80% by mass of an adsorbent, 12 to 75% by mass of a melt-resistant fiber with a high beating degree which is composed of a fiber that has a beating degree of 50 to 500 ml CSF and does not melt at a temperature of 150°C, and 2 to 12% by mass of a binder, wherein said adsorptive composition further comprises 2 to 66% by mass of a melt-resistant fiber with a low beating degree which is composed of a fiber that has a beating degree of 550 to 750 ml CSF and does not melt at a temperature of 150°C. A second aspect is the adsorption sheet according to the first aspect, in which the aforementioned melt-resistant fiber with a high beating degree has an average fiber length of 0.5 to 2.5 mm, an average fiber width of 16 to 35 µm, and an aspect ratio of 30 to 80. A third aspect is the adsorption sheet according to the first aspect, in which the aforementioned melt-resistant fiber with a low beating degree has an average fiber length of 2.6 to 10 mm, an average fiber width of 2 to 10 µm, and an aspect ratio of 300 to 1,250. A fourth aspect is the adsorption sheet according to the first or third aspect, in which a beating degree of fibers obtained by combining the aforementioned melt-resistant fiber with a high beating degree and the aforementioned melt-resistant fiber with a low beating degree is from 50 to 500 ml CSF. A fifth aspect is the adsorption sheet according to the first aspect, in which the aforementioned adsorptive composition either further contains, at a ratio of 25% by mass or less, a hot melt fiber composed of a fiber that melts at a temperature of 150°C, or does not contain the aforementioned hot melt fiber. A sixth aspect is the adsorption sheet according to any one of the first to sixth aspects, in which the aforementioned adsorption sheet has a basis weight of 40 to 150 g/m2. An seventh aspect is a method for producing the adsorption sheet according to any one of the first to sixth aspects, which is a method for producing an adsorption sheet by subjecting a slurry containing the aforementioned adsorptive composition to paper making by a wet papermaking process. [Advantageous Effects of Invention] According to the present invention, the amount of adsorption can be increased by uniformly supporting an adsorbent on a sheet even when the amount of supported adsorbent is increased. [Description of Embodiments] The present invention will be described below based on preferred embodiments. It should be noted that the present invention is not limited only to the embodiments shown below. An adsorption sheet of the present embodiment is a sheet obtained by forming a single layer of an adsorptive composition containing an adsorbent, a melt-resistant fiber and a binder. In the following description, the adsorption sheet may be simply referred to as a "sheet". (Adsorbent) Examples of the adsorbent i